Withdrew 2000 and FNB took 20,000

On Thursday 25 Feb I made a purchase of R68 and withdrew R2000 at the till in Shoprite Mount Edgecombe. I received an sms showing that R2068 was withdrawn from my account. On Saturday morning I get a call to say that my credit card is in arrears and R20,000 was withdrawn. When i called the bank they said it was Shoprites error so i went to shoprite and they printed the receipt showing the amount of R2068. On Monday i called the bank and spoketo Precious who advised that it was the banks fault and they would reverse the money within 24hrs. Yesterday i called the bank again and was told they could fix the problem but would be sorted by close of business. I checked my account this morning and the money has not been put into my account they have charged me R158 for the fees as well. I have debit orders that haven't gone through due to insufficient funds. I am extremely upset as my debit orders have not gone through and my account is now in arrears. Ronald Smith who is the credit manager and Precious seem to be ignoring my messages and calls. I think its time to get lawyers involved.